Math Problem Statement

A polynomial function P and its graph are given. P(x) = 3x4 + x3 − 9x2 − 9x − 2

The x y-coordinate plane is given. The curve enters the window in the second quadrant, goes down and right becoming less steep, changes direction at the point (−1, 0), goes up and right becoming more steep, passes through the approximate point (−0.8, 0.2), goes up and right becoming less steep, changes direction at the approximate point (−0.6, 0.3), goes down and right becoming more steep, crosses the x-axis at approximately x = −0.3, crosses the y-axis at y = −2, passes through the approximate point (0.6, −10.5), goes down and right becoming less steep, changes direction at the approximate point (1.3, −18.2), goes up and right becoming more steep, crosses the x-axis at x = 2, and exits the window in the first quadrant. (a) List all possible rational zeros of P given by the Rational Zeros Theorem. (Enter your answers as a comma-separated list.) x =

Correct: Your answer is correct. Nicely done! (b) From the graph, determine which of the possible rational zeros actually turn out to be zeros. (Enter your answers as a comma-separated list. Enter all answers using the appropriate multiplicities.) x =

Incorrect: Your answer is incorrect.

Solution

Let's solve the problem step by step.

Part (a) - List all possible rational zeros of P(x)P(x) given by the Rational Zeros Theorem.

The Rational Zeros Theorem states that any rational zero of a polynomial P(x)P(x) is of the form pq\frac{p}{q}, where:

  • pp is a factor of the constant term (in this case, the constant term is 2-2).
  • qq is a factor of the leading coefficient (in this case, the leading coefficient is 33).

Step 1: Factors of the constant term (2-2) The factors of 2-2 are ±1,±2\pm 1, \pm 2.

Step 2: Factors of the leading coefficient (33) The factors of 33 are ±1,±3\pm 1, \pm 3.

Step 3: List all possible rational zeros Now, we combine all the factors of pp and qq to form possible rational zeros pq\frac{p}{q}.

The possible rational zeros are:

  • ±1,±13,±2,±23\pm 1, \pm \frac{1}{3}, \pm 2, \pm \frac{2}{3}.

So, the possible rational zeros of the polynomial are: 1,1,13,13,2,2,23,23.\boxed{1, -1, \frac{1}{3}, -\frac{1}{3}, 2, -2, \frac{2}{3}, -\frac{2}{3}}.


Part (b) - From the graph, determine which of the possible rational zeros are actually zeros.

Let's analyze the graph based on the information provided:

  • The curve changes direction at (1,0)(-1, 0), which means x=1x = -1 is a zero.
  • The curve crosses the x-axis again at x2x \approx 2, which means x=2x = 2 is another zero.

From the given graph, the zeros appear to be x=1x = -1 and x=2x = 2.

So, the rational zeros that actually turn out to be zeros are: 1,2.\boxed{-1, 2}.


Let me know if you'd like further clarification or if you'd like to dive into the next steps! Here are some related questions:

  1. How do you use synthetic division to test a potential zero?
  2. How can you find the multiplicity of a root from the graph?
  3. What is the significance of the graph changing direction at a zero?
  4. How can you factor a polynomial completely once you know some zeros?
  5. What does the end behavior of a polynomial function tell you about its degree?

Tip: When you're working with rational zeros, always test the potential zeros systematically by plugging them into the polynomial or using synthetic division!

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Math Problem Analysis

Mathematical Concepts

Polynomial Functions
Rational Zeros Theorem
Graph Analysis

Formulas

Rational Zeros Theorem: Rational zeros are of the form p/q, where p is a factor of the constant term and q is a factor of the leading coefficient.

Theorems

Rational Zeros Theorem

Suitable Grade Level

Grades 9-11